The goals of the proposed research are to better understand inhibition processes and the role of inhibition in disruptive behavior disorders (DBD). Specifically, the first goal of the project is to better understand the relation between motivational and executive inhibition. Analyses will test for evidence of convergent and discriminant validity among four commonly employed laboratory measures of motivational and/or executive inhibition. To our knowledge, no study has been conducted using all four measures in the same sample. The second goal of the project is to compare the validity of two of the most widely recognized theories that have been put forth to understand the primary deficit in DBD (i.e., motivational and executive inhibition theories). Analyses will test whether the motivational tasks are tapping differential variance than the executive tasks in each DBD (i.e., ADHD, ODD, and CD). In only a minority of studies has task performance been measured in relation to all the DBD dimensions. Specific hypotheses are that measures of motivational inhibition will account for more variance in ODD and CD and measures of executive inhibition will account for more variance in ADHD. The results of this study will be important for furthering our understanding of the role of inhibition in DBD which will inform (1) future research (e.g., neuroimaging studies; genetic studies), (2) treatment (e.g., medication; behavior modification), and (3) prevention (e.g., early identification; development of prevention programs).